We are now entering the closing weeks of what promises to be yet another close and contentious presidential election contest. As each side seeks to maximise its advantages and minimise its weaknesses, the Republican party has chosen the lowest of low roads, engaging in two sleazy political marketing campaigns over the past week.

First, DVDs of an anti-Muslim documentary film are being distributed to 28 million voters in swing states like Florida, Pennsylvania, Ohio, Michigan, Colorado and Wisconsin. Second, Republican telemarketers have begun push polling aimed at scaring Jewish voters in swing states from voting for Barack Obama.

The 2005 film, called Obsession: Radical Islam's War Against the West, warns that Islamic jihadists aim to take over the US government and destroy our way of life and urges voters to consider which candidate will best protect the nation. Among other subtleties, the film attempts to equate Islam with Nazism, juxtaposing scenes of children being encouraged to become suicide bombers with shots of Nazi rallies.

The film was distributed as an advertising supplement in major newspapers, including the New York Times. In addition, the Republican Jewish Coalition has mailed the DVDs to rabbis and Jewish organisational mailing lists, while a Christian Zionist group distributed it to delegates at the Republican and Democratic conventions. Sheldon Adelson, a major funder of arch-conservative causes and Likud party leader Bibi Netanyahu, personally gives the DVD to participants in the Taglit Birthright Israel tours he funds for Jewish young people.

The film's production and promotional campaign were bankrolled by the Clarion Fund, an obscure non-profit that has not filed the required IRS form that would allow the public to see who its officers and major funders are. The group was founded, however, by Raphael Shore, an Israeli-Canadian citizen and supporter of John McCain. Shore's website, Radical Islam, featured an editorial endorsing McCain for president. That's a big no-no: 501c3s aren't legally allowed to endorse candidates.

The mass distribution of Obsession is an obvious Republican scare-tactic, right out of the Rovian playbook. Party operatives believe that scaring Americans into believing there's a jihadist under every bed will play to Republican strengths and Democratic weaknesses on national security. They swiftboated John Kerry in 2004. Now they're jihadising Barack Obama.

To this end, Jewish voters in swing states have also been the targets of push polling from Republican-affiliated marketing outfits. Joelna Marcus of Key West, Florida received a telemarketing call asking if she is Jewish. After replying "yes", she was asked whether she was religious. Then the push poller then asked her if her opinion of Barack Obama would change if she knew that Obama had given lots and lots of money to the PLO. In Pittsburgh, Pennsylvania, Debbie Minden received a call asking whether her support for Obama would be swayed if she knew "his church was anti-Israel" or that Hamas endorsed him and that its leaders had met with him. The caller also asked if she would change her mind if she learned he was Muslim.

The New Republic's Jonathan Cohn also received a call in Michigan and took notes of the smears: According to the caller, some of Obama's best friends in Chicago were "pro-Palestinian leaders"; Jimmy Carter's anti-Israel national security adviser Zbigniew Brzezinski is an Obama foreign policy adviser; Obama sat on a board which funded a "pro-Palestinian charity"; Obama said that if elected he would call for a summit of Muslim nations and exclude Israel.

Minden reported that her call came from a firm called Research Strategies, which is none other than Wilson Research Strategies, whose founder is Chris Wilson. Wilson is a top Republican consultant and friend of, you guessed it, Karl Rove. Cohn said his call came from a company called Central Marketing, which has done push polls on behalf of the campaigns of Republicans John Thune and Michael Bloomberg.

The way these things work, McCain has plausible deniability because the calls aren't made by his campaign. But they and the DVD are clearly designed to raise fears about national security and suppress Jewish turnout for Obama. If Republicans can reduce the number of Obama voters in key swing states by a few percentage points, they figure they strengthen McCain's chances of winning. This is American presidential politics at its most disgusting.